Clinical and animal studies of eyes with hypotony will be performed to evaluate the mechanisms of hypotony. Experimental models of ciliochoroidal detachment, retinal detachment, and cyclodialysis in monkeys have been developed which result in hypotony. Aqueous flow studies and vitreous flow studies will be performed in these models by use of radioisotope tracers and fluorophotometry. In addition, aqueous flow by flurophotometry will be measured in cases of hypotony. A drug combination of methacholine plus eserine has been shown to reverse experimental hypotony by reducing uvecscleral aqueous outflow. Additional drugs will be investigated for potential use in the treatment of ocular hypotony.